Abstract 1925: Incidence and Predictors of Drug Eluting Stent Fracture in Human Coronary Artery - Pathologic Analysis
Background Stent fractures (SF) have been reported clinically to occur in 1–2% of cases by angiography after drug-eluting stent (DES) implantation. However, no pathologic study of stent fracture following radiographic examination at autopsy is available.
Methods We reviewed high-contrast film-based radiographs of 116 consecutive cases (160 lesions) from CVPath DES registry by light microscopy (x40). SFs were classified as minor (1 or 2 struts fracture), moderate (> 2 struts fracture), and severe (complete separation). Severity of calcification was assessed in the stented region and recorded as none, mild (single focus), moderate (discreet multiple foci), and severe (most of the stented region).
Results Of the 160 lesion, 147 free of artifacts were included in the study. SFs were documented in 41 lesions (28%) (minor 12, moderate 24, severe 5). Lesions with SF vs. without SF had longer implant duration (337±429days vs. 160±237days, p=0.002), higher Cypher stent usage (61% vs. 38%, p=0.01), longer stent length (30.9±13.4 mm vs. 21.5±11.0 mm, p<0.0001), greater number of stents (1.7±0.9 vs. 1.3±0.6, p=0.002), and a higher incidence of overlapping stents (39% vs. 21%, p=0.03). Event rates defined as stent thrombosis or restenosis were higher in those with severe SF compared to those without SF (80% vs. 36%, p=0.04). Longer stent length, use of Cypher vs. Taxus, longer duration, and bifurcation lesion were identified as independent risk factors of stent fracture by multiple logistic regression analysis. However, minimal and moderate SF had no significant association with events as compared to without SF (39% vs. 36%, p=0.72). Calcification severity was similar in stents with or without fracture.
Conclusion Stent fractures were observed in 28% of lesions at autopsy. Severe stent fractures are significantly more often seen in Cypher stents and are associated with thrombosis or restenosis however, minor and moderate fractures have no clinical impact.